I have recently encountered a problem when trying to open most of their pdfs that they have been referencing for years on pc. Adobe reader sas "Adobe Reader could not open 'file.pdf' because it is either not a supported file type or because the file has been damaged (for example, it was sent as an email attachment and wasn't correctly decoded.

I have tried various programs to recover/restore/repair them, they all say the files aren't PDF files.


closed as unclear what you're asking by Ƭᴇcʜιᴇ007, Kevin Panko, DavidPostill, Matthew Williams, Raystafarian Dec 4 '14 at 13:04

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • Is it ANY PDF or just select ones? Can the problematic ones be opened on other computers? Have you tried other PDF readers? Have you confirmed there was no disk/file-system corruption on the source computer? If you've tried several recovery programs and they can't identify them, then I'm not sure what you expect from us.. What's your actual question? – Ƭᴇcʜιᴇ007 Dec 2 '14 at 17:11

This is a new security check, added to Adobe Reader.
You can turn it off in the bValidateBytesBeforeHeader registry keys as shown in the link above.
But, be careful - it is possible that the reason your PDF documents are failing the additional security check is because they've been tampered with or infected. This is more likely than you might expect, so be sure to virus scan those PDFs before you go opening them.
Edit: The registry keys given are:
HKCU\Software\Adobe\(product name)\(version)\AVGeneral\bValidateBytesBeforeHeader - which is a DWORD value, and should be set to 0 to skip the check.
The product name and product version will look something like:
HKCU\Software\Adobe\Acrobat Reader\11.0\AVGeneral
The above key is in the HKEY_CURRENT_USER hive, and will only affect the current user. Another key is located in the same path under HKEY_LOCAL_MACHINE (HKLM).
Also, note that if you have installed a 32-bit version of Adobe Reader on 64-bit Windows, you will have to add Wow6432Node in between Software and Adobe, eg: HKCU\Software\Wow6432node\Adobe\Acrobat Reader....

  • Can you copy the parts about the registry (its location etc) to your post, in case the link becomes invalid? – LPChip Dec 2 '14 at 18:47

you can check your pdf files with another PC or system, or maybe if you re-install adobe pdf reader your problem will be fix, we have several app for reading pdf like foxit reader , you can check them too.

if your problem not fix after all you can check your system by antivirus or anti malicious programs , maybe it's infected by virus,trojan or etc !

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